Three speed, Reversible. Select speed (1-low, 2-medium or 3-high). Select fan-blade direction (Out-exhaust or In-for air intake). Open dome manually with hand knob. When opened approximately 2”, fan blade is activated. Placing the In/Out switch in the center (neutral) position can turn off fan blade. Dimensions: 16 ½” x 16 ½” 3 ½” CSA/UL Certified